P0302 P0300 issues.
 

Here is the breakdown.

Drove my car to mazdatrix to get a compression test and hopefully get worked on from an extended warranty company. when I am sitting at idle for 30 seconds or more the engine starts to stumble here and there.

Service tech tried to pull codes but none could be found.

Compression test gets done

Front 6.1,5.6,6.8 @216
Rear 6.7,7.0,6.9 @215

So there we have it low compression! I decide to leave the vehicle there to get serviced.

I come back a few days later to install the stock pulleys so the engine looks stock and un-tampered with I go to start the car no dice. So we hook up a portable jumper and it fires right up. No codes everything's fine I leave.

The warranty adjuster comes by to see the compression test and test drive the car. Warranty company denies my claim due to modifications that have been made to the car (Springs).

I go to pick up the car and about 30 seconds later the MIL turns on. my first guess is its picking up that the eccentric shaft sensor was removed. so i dont bother with it. My friend who drive me down hooks up an obdII reader to it and pulls a misfire code.

He clears it I fire it up all seems fine. I start driving again and MIL comes back on. Get home and check all the connections the rear rotor Trailing spark plug wire is loose so I snap it back in place clear codes and it comes back again.

So I pull the plugs they look ok. but I decide to replace them anyway. Clear codes Drive around again MIL comes back on. Except now its reading a P0300(random misfire) I test the wires they ohm out fine, coil packs ohm out fine, cleaned the MAF, cleaned the ESS connection, charged the battery, did an oil change, checked for coolant leaks, inspected all intake related components no cracks. The only thing I havent checks is the fuel pump or injectors. Oh and the engine is running rich as hell, it burns the eyes.

Mill is still flashing at random rpms usually in the 2.5-3.5range. All FF data is 2.8 to 3.5 FF data shows all sensors working fine.

Im truly stumped.

My main questions...

If it is compression then why did it not show codes before? Why did it only show codes afterward?

Could something have been damaged (besides coils,plugs,wires) from driving 20 miles with a lead wire not properly seated on the spark plug?

It clearly started after the compression test so that's the catalyst now whats the issue?

Why did the P0302 change to a P0300 after changing spark plugs?

Why is it running so rich when all the ignition components check out fine?

Any useful advice is much appreciated.

Wow I didn't know your 8 was that bad shady. This is a super messed up situation. The worse part I think is that damn warranty Guy saying spring off all things is messing up you motor. What a as fuck... :icon_no2:

nah they didn't say that's what caused the issue. that was just their way of getting out of the contract.

I think even if the ignition coils are within mazda specs they still could be failing. P0301 is the front rotor P0302 is the rear rotor. A P0300 does not tell you specifically which cylinder(s) is/are mis-firing, nor why.

How many miles are you on your ignition coils?

A code P0300 may mean that one or more of the following has happened:

•Faulty spark plugs or wires
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector(s)
•Burned exhaust valve
•Faulty catalytic converter(s)
•Stuck/blocked EGR valve / passages
•Faulty camshaft position sensor
•Defective computer

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak
in the intake manifold or unmetered air getting past the airflow sensor

OK Try this the ESS reset. Turn the car to on but do not start. Press the brake pedal 20 times in a 8 second or period. If done right the oil pressure guage will sweep. When ever you change pulleys and or belts you need to do that.

^+1

Its funny that I did every single thing in the book. tested everything and the simplest easiest possible thing was the cause.

Invasion thank you so much I owe you a beer. Have a yuengling for me since I cant enjoy one on the west coast.

Yeah, that might just do it............resetting. You gotta pump the brake pedal pretty fast. If the oil gauge doesn't do the sweep, then turn off the car, turn it back on(no start) and try it again until it does! Once it does do the sweep, then turn the car off for a minute or so, then start as normal(and after warm-up)......go for a drive.


EDIT: Oooops! It looks like as I was typing, you did it and that was it!

Still doesn't explain the supposed low compression numbers though?????

And......how many miles on those coils.....even though you tested them?

8k on the coils.

Compression is a bad apex/side seal. Rebuild will commence in 3 months.

I have the same error code P0300 i will try to do the reset pumping the brake pedal 20 times and see if that work